Combination ultrasonic and electrosurgical instrument with adjustable energy modalities and method for limiting blade temperature

ABSTRACT

An ultrasonic surgical instrument and method of limiting an ultrasonic blade temperature includes adjusting at least one power parameter of the ultrasonic energy in response to reaching a predetermined frequency parameter change threshold in the ultrasonic blade limiting the temperature of the ultrasonic blade to an upper temperature limit. The ultrasonic surgical instrument further includes an end effector having an ultrasonic blade, a jaw, and a controller. The jaw is movably positioned relative to the ultrasonic blade and configured to move between an open position and a closed position. The controller operatively connects to the ultrasonic blade and is configured to measure an ultrasonic frequency of the ultrasonic blade. The controller has a memory including a plurality of predetermined data correlations that correlate changes in measured ultrasonic frequency of the ultrasonic blade to a blade temperature of the ultrasonic blade.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Pat. App. No.62/509,336, entitled “Control Algorithm for Surgical Instrument withUltrasonic and Electrosurgical Modalities,” filed May 22, 2017, thedisclosure of which is incorporated by reference herein.

BACKGROUND

Ultrasonic surgical instruments utilize ultrasonic energy for bothprecise cutting and controlled coagulation. Ultrasonic energy cuts andcoagulates by vibrating a blade in contact with tissue. Vibrating atfrequencies of approximately 55.5 kilohertz (kHz), for example, theultrasonic blade denatures protein in the tissue to form a stickycoagulum. Pressure exerted on the tissue with the blade surfacecollapses blood vessels and allows the coagulum to form a hemostaticseal. The precision of cutting and coagulation may be controlled by thesurgeon's technique and adjusting the power level, blade edge, tissuetraction, and blade pressure, for example.

Examples of ultrasonic surgical devices include the HARMONIC ACE®Ultrasonic Shears, the HARMONIC WAVE® Ultrasonic Shears, the HARMONICFOCUS® Ultrasonic Shears, and the HARMONIC SYNERGY® Ultrasonic Blades,all by Ethicon Endo-Surgery, Inc. of Cincinnati, Ohio. Further examplesof such devices and related concepts are disclosed in U.S. Pat. No.5,322,055, entitled “Clamp Coagulator/Cutting System for UltrasonicSurgical Instruments,” issued Jun. 21, 1994, the disclosure of which isincorporated by reference herein; U.S. Pat. No. 5,873,873, entitled“Ultrasonic Clamp Coagulator Apparatus Having Improved Clamp Mechanism,”issued Feb. 23, 1999, the disclosure of which is incorporated byreference herein; U.S. Pat. No. 5,980,510, entitled “Ultrasonic ClampCoagulator Apparatus Having Improved Clamp Arm Pivot Mount,” issued Nov.9, 1999, the disclosure of which is incorporated by reference herein;U.S. Pat. No. 6,283,981, entitled “Method of Balancing AsymmetricUltrasonic Surgical Blades,” issued Sep. 4, 2001, the disclosure ofwhich is incorporated by reference herein; U.S. Pat. No. 6,309,400,entitled “Curved Ultrasonic Blade having a Trapezoidal Cross Section,”issued Oct. 30, 2001, the disclosure of which is incorporated byreference herein; U.S. Pat. No. 6,325,811, entitled “Blades withFunctional Balance Asymmetries for use with Ultrasonic SurgicalInstruments,” issued Dec. 4, 2001, the disclosure of which isincorporated by reference herein; U.S. Pat. No. 6,423,082, entitled“Ultrasonic Surgical Blade with Improved Cutting and CoagulationFeatures,” issued Jul. 23, 2002, the disclosure of which is incorporatedby reference herein; U.S. Pat. No. 6,773,444, entitled “Blades withFunctional Balance Asymmetries for Use with Ultrasonic SurgicalInstruments,” issued Aug. 10, 2004, the disclosure of which isincorporated by reference herein; U.S. Pat. No. 6,783,524, entitled“Robotic Surgical Tool with Ultrasound Cauterizing and CuttingInstrument,” issued Aug. 31, 2004, the disclosure of which isincorporated by reference herein; U.S. Pat. No. 8,057,498, entitled“Ultrasonic Surgical Instrument Blades,” issued Nov. 15, 2011, thedisclosure of which is incorporated by reference herein; U.S. Pat. No.8,461,744, entitled “Rotating Transducer Mount for Ultrasonic SurgicalInstruments,” issued Jun. 11, 2013, the disclosure of which isincorporated by reference herein; U.S. Pat. No. 8,591,536, entitled“Ultrasonic Surgical Instrument Blades,” issued Nov. 26, 2013, thedisclosure of which is incorporated by reference herein; U.S. Pat. No.8,623,027, entitled “Ergonomic Surgical Instruments,” issued Jan. 7,2014, the disclosure of which is incorporated by reference herein; andU.S. Pub. No. 2016/0022305, entitled “Ultrasonic Blade Overmold,”published Jan. 28, 2016, issued as U.S. Pat. No. 9,750,521 on Sep. 5,2017, the disclosure of which is incorporated by reference herein.

Electrosurgical instruments utilize electrical energy for sealingtissue, and generally include a distally mounted end effector that canbe configured for bipolar or monopolar operation. During bipolaroperation, electrical current is provided through the tissue by activeand return electrodes of the end effector. During monopolar operation,current is provided through the tissue by an active electrode of the endeffector and a return electrode (e.g., a grounding pad) separatelylocated on a patient's body. Heat generated by the current flowingthrough the tissue may form hemostatic seals within the tissue and/orbetween tissues, and thus may be particularly useful for sealing bloodvessels, for example. The end effector of an electrosurgical device mayalso include a cutting member that is movable relative to the tissue andthe electrodes to transect the tissue.

Electrical energy applied by an electrosurgical device can betransmitted to the instrument by a generator coupled with theinstrument. The electrical energy may be in the form of radio frequency(“RF”) energy, which is a form of electrical energy generally in thefrequency range of approximately 300 kilohertz (kHz) to 1 megahertz(MHz). In use, an electrosurgical device can transmit such energythrough tissue, which causes ionic agitation, or friction, in effectresistive heating, thereby increasing the temperature of the tissue.Because a sharp boundary is created between the affected tissue and thesurrounding tissue, surgeons can operate with a high level of precisionand control, without sacrificing un-targeted adjacent tissue. The lowoperating temperatures of RF energy may be useful for removing,shrinking, or sculpting soft tissue while simultaneously sealing bloodvessels. RF energy works particularly well on connective tissue, whichis primarily comprised of collagen and shrinks when contacted by heat.

An example of an RF electrosurgical device is the ENSEAL® Tissue SealingDevice by Ethicon Endo-Surgery, Inc., of Cincinnati, Ohio. Furtherexamples of electrosurgical devices and related concepts are disclosedin U.S. Pat. No. 6,500,176 entitled “Electrosurgical Systems andTechniques for Sealing Tissue,” issued Dec. 31, 2002, the disclosure ofwhich is incorporated by reference herein; U.S. Pat. No. 7,112,201entitled “Electrosurgical Instrument and Method of Use,” issued Sep. 26,2006, the disclosure of which is incorporated by reference herein; U.S.Pat. No. 7,125,409, entitled “Electrosurgical Working End for ControlledEnergy Delivery,” issued Oct. 24, 2006, the disclosure of which isincorporated by reference herein; U.S. Pat. No. 7,169,146 entitled“Electrosurgical Probe and Method of Use,” issued Jan. 30, 2007, thedisclosure of which is incorporated by reference herein; U.S. Pat. No.7,186,253, entitled “Electrosurgical Jaw Structure for Controlled EnergyDelivery,” issued Mar. 6, 2007, the disclosure of which is incorporatedby reference herein; U.S. Pat. No. 7,189,233, entitled “ElectrosurgicalInstrument,” issued Mar. 13, 2007, the disclosure of which isincorporated by reference herein; U.S. Pat. No. 7,220,951, entitled“Surgical Sealing Surfaces and Methods of Use,” issued May 22, 2007, thedisclosure of which is incorporated by reference herein; U.S. Pat. No.7,309,849, entitled “Polymer Compositions Exhibiting a PTC Property andMethods of Fabrication,” issued Dec. 18, 2007, the disclosure of whichis incorporated by reference herein; U.S. Pat. No. 7,311,709, entitled“Electrosurgical Instrument and Method of Use,” issued Dec. 25, 2007,the disclosure of which is incorporated by reference herein; U.S. Pat.No. 7,354,440, entitled “Electrosurgical Instrument and Method of Use,”issued Apr. 8, 2008, the disclosure of which is incorporated byreference herein; U.S. Pat. No. 7,381,209, entitled “ElectrosurgicalInstrument,” issued Jun. 3, 2008, the disclosure of which isincorporated by reference herein.

Additional examples of electrosurgical devices and related concepts aredisclosed in U.S. Pat. No. 8,939,974, entitled “Surgical InstrumentComprising First and Second Drive Systems Actuatable by a Common TriggerMechanism,” issued Jan. 27, 2015, the disclosure of which isincorporated by reference herein; U.S. Pat. No. 9,161,803, entitled“Motor Driven Electrosurgical Device with Mechanical and ElectricalFeedback,” issued Oct. 20, 2015, the disclosure of which is incorporatedby reference herein; U.S. Pub. No. 2012/0078243, entitled “ControlFeatures for Articulating Surgical Device,” published Mar. 29, 2012,issued as U.S. Pat. No. 9,877,720 on Jan. 30, 2018, the disclosure ofwhich is incorporated by reference herein; U.S. Pat. No. 9,402,682,entitled “Articulation Joint Features for Articulating Surgical Device,”issued Aug. 2, 2016, the disclosure of which is incorporated byreference herein; U.S. Pat. No. 9,089,327, entitled “Surgical Instrumentwith Multi-Phase Trigger Bias,” issued July 28, 2015, the disclosure ofwhich is incorporated by reference herein; U.S. Pat. No. 9,545,253,entitled “Surgical Instrument with Contained Dual Helix ActuatorAssembly,” issued Jan. 17, 2017, the disclosure of which is incorporatedby reference herein; and U.S. Pat. No. 9,572,622, entitled “BipolarElectrosurgical Features for Targeted Hemostasis,” issued Feb. 21, 2017,the disclosure of which is incorporated by reference herein.

Some instruments may provide ultrasonic and RF energy treatmentcapabilities through a single surgical device. Examples of such devicesand related methods and concepts are disclosed in U.S. Pat. No.8,663,220, entitled “Ultrasonic Surgical Instruments,” issued Mar. 4,2014, the disclosure of which is incorporated by reference herein; U.S.Pub. No. 2015/0141981, entitled “Ultrasonic Surgical Instrument withElectrosurgical Feature,” published May 21, 2015, issued as U.S. Pat.No. 9,949,785 on Apr. 24, 2018, the disclosure of which is incorporatedby reference herein; and U.S. Pub. No. 2017/0000541, entitled “SurgicalInstrument with User Adaptable Techniques,” published Jan. 5, 2017,issued as U.S. Pat. No. 11,141,213 on Oct. 12, 2021, the disclosure ofwhich is incorporated by reference herein.

While various types of ultrasonic surgical instruments andelectrosurgical instruments, including combinationultrasonic-electrosurgical devices, have been made and used, it isbelieved that no one prior to the inventor(s) has made or used theinvention described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate embodiments of the invention,and, together with the general description of the invention given above,and the detailed description of the embodiments given below, serve toexplain the principles of the present invention.

FIG. 1 depicts a schematic view of an exemplary ultrasonic surgicalinstrument including a shaft assembly and a handle assembly operativelyconnected to an ultrasonic generator;

FIG. 2A depicts a side view of an end effector of the ultrasonicsurgical instrument of FIG. 1 showing the end effector in an openconfiguration for receiving tissue of a patient;

FIG. 2B depicts the side view of the end effector of FIG. 2A, but withthe end effector in a closed configuration for clamping the tissue ofthe patient;

FIG. 3 depicts a flowchart of a high-level method of controlling a bladetemperature of the ultrasonic surgical system of FIG. 1;

FIG. 4 depicts a flowchart of a version of the method of controlling theblade temperature of FIG. 3; and

FIG. 5 depicts a graph of ultrasonic frequency of the ultrasonic energyfor the version in FIG. 4 with an ultrasonic frequency cap.

The drawings are not intended to be limiting in any way, and it iscontemplated that various embodiments of the invention may be carriedout in a variety of other ways, including those not necessarily depictedin the drawings. The accompanying drawings incorporated in and forming apart of the specification illustrate several aspects of the presentinvention, and together with the description serve to explain theprinciples of the invention; it being understood, however, that thisinvention is not limited to the precise arrangements shown.

DETAILED DESCRIPTION

The following description of certain examples of the invention shouldnot be used to limit the scope of the present invention. Other examples,features, aspects, embodiments, and advantages of the invention willbecome apparent to those skilled in the art from the followingdescription, which is by way of illustration, one of the best modescontemplated for carrying out the invention. As will be realized, theinvention is capable of other different and obvious aspects, all withoutdeparting from the invention. Accordingly, the drawings and descriptionsshould be regarded as illustrative in nature and not restrictive.

I. Exemplary Surgical System

FIG. 1 illustrates one example of a surgical system (10) including asurgical instrument (12) and a generator (14) coupled via a cable (16).Surgical instrument (12) has a proximally positioned handle assembly(18), which may also be referred to as a handpiece, a distallypositioned end effector (20), a shaft assembly (22) extendingtherebetween, and an ultrasonic transducer (24). End effector (20)generally includes a clamp arm (26) pivotally connected relative to anultrasonic blade (28) and configured to pivot from an open position ofan open configuration to a closed position of a closed configuration asdiscussed below in greater detail. Ultrasonic blade (28) is acousticallycoupled with ultrasonic transducer (24) via an acoustic waveguide (notshown) for providing ultrasonic energy to ultrasonic blade (28). Inaddition, end effector (20) further includes a plurality of RFelectrodes (30) positioned therealong for contacting the tissue ineither the open or closed position as desired by a clinician. Generator(14) operatively connects to ultrasonic blade (28) and RF electrodes(30) to respectively provide ultrasonic energy and RF energy toultrasonic blade (28) and RF electrodes (30) to thereby cut and/or sealthe tissue is use.

In some versions, clamp arm (26) has two or more electrodes (30). Insome such versions, electrodes (30) of clamp arm are capable of applyingbipolar RF energy to tissue. In some such versions, ultrasonic blade(28) remains electrically neutral, such that ultrasonic blade (28) isnot part of the RF circuit. In some other versions, ultrasonic blade(28) forms part of the RF circuit, such that ultrasonic blade (28)cooperates with one or more electrodes (30) of clamp arm (26) to applybipolar RF energy to tissue. By way of example only, some versions ofclamp arm (26) may have just one electrode (30) that serves as an activepole for RF energy; while ultrasonic blade (28) provides a return polefor RF energy. Thus, the term “electrodes (30)” should be read toinclude versions where clamp arm (26) has only one single electrode.

It should be understood that terms such as “proximal” and “distal” areused herein with reference to surgical instrument (12). Thus, endeffector (20) is distal with respect to the more proximal handleassembly (18). It will be further appreciated that for convenience andclarity, spatial terms such as “upper” and “lower” are used herein withrespect to the drawings. However, surgical instruments are used in manyorientations and positions, and these terms are not intended to belimiting and absolute. Likewise, terms such as “instrument” and “device”as well as “limit” and “cap” may be used interchangeably.

A. Exemplary Generator

With reference to FIG. 1, generator (14) drives a combination surgicalinstrument (12) with both ultrasonic and RF energies. Generator (14) isshown separate from surgical instrument (12) in the present example,but, alternatively, generator (14) may be formed integrally withsurgical instrument (12) to form a unitary surgical system. Generator(14) generally includes an input device (32) located on a front panel(34) of generator (14). Input device (32) may have any suitable devicethat generates signals suitable for programming the operation ofgenerator (32). For example, in operation, the clinician may program orotherwise control operation of generator (32) using input device (32)(e.g., by one or more processors contained in the generator) to controlthe operation of generator (14) (e.g., operation of the ultrasonicgenerator drive circuit (not shown) and/or RF generator drive circuit(not shown)).

In various forms, input device (32) includes one or more buttons,switches, thumbwheels, keyboard, keypad, touch screen monitor, pointingdevice, remote connection to a general purpose or dedicated computer. Inother forms, input device (32) may having a suitable user interface,such as one or more user interface screens displayed on a touch screenmonitor. Accordingly, the clinician may selectively set or programvarious operating parameters of the generator, such as, current (I),voltage (V), frequency (f), and/or period (T) of a drive signal orsignals generated by the ultrasonic and RF generator drive circuits (notshown). Specifically, in the present example, generator (32) isconfigured to deliver various power states to the surgical instrument(10) that include, but are not necessarily limited to, only ultrasonicenergy, only RF energy, and a combination of ultrasonic and RF energies,which simultaneously powers ultrasonic blade (28) and RF electrodes(30). It will be appreciated that input device (32) may have anysuitable device that generates signals suitable for programming theoperation of generator (14) and should not be unnecessarily limited toinput device (32) shown and described herein.

By way of example only, generator (14) may comprise a GEN04 or GEN11sold by Ethicon Endo-Surgery, Inc. of Cincinnati, Ohio. In addition, orin the alternative, generator (14) may be constructed in accordance withat least some of the teachings of U.S. Pub. No. 2011/0087212, entitled“Surgical Generator for Ultrasonic and Electrosurgical Devices,”published Apr. 14, 2011, issued as U.S. Pat. No. 8,986,302 on Mar. 24,2015, the disclosure of which is incorporated by reference herein.

B. Exemplary Surgical Instrument

Surgical instrument (10) of the present example shown in FIG. 1 includesa plurality of energy inputs, which are more particularly referred toherein as an upper button (36), lower button (38), and side button (40).By way of example, upper button (36) is configured to direct generator(14) to power ultrasonic transducer (24) with a maximum ultrasonicenergy output, whereas lower button (38) is configured to directgenerator (14) to power ultrasonic transducer (24) with a lowerultrasonic energy output. By way of further example, side button (40) isconfigured to direct generator (14) to power ultrasonic transducer (24)with a pulsed energy output, such as 5 continuous signals and 5 or 4 or3 or 2 or 1 pulsed signals. In one or more examples, the specific drivesignal configuration directed by energy inputs may be controlled and/orbased upon EEPROM settings in generator (14) and/or user power levelselection(s). By way of further example, surgical instrument (10) mayinclude a two-button configuration for selectively directing ultrasonicand RF energies as described herein. Various examples of instrumentshaving two-button input configurations are described in various patentreferences cited herein. In any case, it will be appreciated that theinvention described herein is not intended to be unnecessarily limitedto a particular input button, switch, etc. to the extent that any formof input may be so used.

Surgical instrument (12) further includes a first data circuit (42) anda second data circuit (44) in communication with generator (14). Forexample, first data circuit (42) indicates a burn-in frequency slope.Additionally or alternatively, any type of information may becommunicated to second data circuit (42) for storage therein via a datacircuit interface (e.g., using a logic device). Such information maycomprise, for example, an updated number of operations in which surgicalinstrument (12) has been used and/or dates and/or times of its usage. Inother examples, second data circuit (44) may transmit data acquired byone or more sensors (e.g., an instrument-based temperature sensor). Instill other examples, second data circuit (44) may receive data fromgenerator (14) and provide an indication to a clinician (e.g., an LEDindication or other visible indication) based on the received data toand/or from surgical instrument (12). In the present example, seconddata circuit (44) stores information about the electrical and/orultrasonic properties of an associated transducer (24) and/or endeffector (20), which includes data measured and collected fromultrasonic blade (28) and/or RF electrodes (30).

To this end, various processes and techniques described herein areperformed by a controller (46), which includes internal logic. In oneexample, controller (46) has at least one processor and/or othercontroller device in communication with generator (14), ultrasonic blade(28), RF electrodes (30), and other inputs and outputs described hereinfor monitoring and performing such processes and techniques. In oneexample, controller (46) has a processor configured to monitor userinput provided via one or more inputs and capacitive touch sensors.Controller (46) may also include a touch screen controller to controland manage the acquisition of touch data from a capacitive touch screen.

With reference to FIGS. 1-2B, handle assembly (18) further includes atrigger (48) operatively connected to clamp arm (26). Trigger (48) andclamp arm (26) are generally biased toward the unactuated, openconfiguration. However, selectively manipulating trigger (48) proximallypivots clamp arm (26) toward ultrasonic blade (28) from the openposition to the closed position. As used in the present example, clamparm (26) and ultrasonic blade (28) may also be generally referred torespectively as upper and lower jaws of surgical instrument (12). In theopen position, clamp arm (26) and ultrasonic blade (28) are configuredto receive the tissue, whereas clamp arm (26) is configured to clamptissue against ultrasonic blade (28) for grasping, sealing, and/orcutting the tissue.

Ultrasonic blade (28) ultrasonically vibrates to seal and/or cut thetissue, whereas RF electrodes (30) provide electrical power to thetissue. RF electrodes (30) of the present example are all electricallysimilar electrodes with ultrasonic blade (28) also electricallyconnected as a return electrode. As used therein, the term “electrode”may thus apply to both RF electrodes (30) and ultrasonic blade (28) withrespect to the RF electrical circuit. Without tissue, the electricalcircuit from RF electrodes (30) to ultrasonic blade (28) is open,whereas the electrical circuit is closed by the tissue between RFelectrode (30) and ultrasonic blade (28) in use. RF electrodes (30) maybe activated to apply RF energy alone or in combination with ultrasonicactivation of ultrasonic blade (28). For example, activating only RFelectrodes (30) to apply RF energy alone may be used for spotcoagulating without concern for inadvertently cutting tissue withultrasonically activated ultrasonic blade (28). However, the combinationof ultrasonic energy and RF energy may be used for sealing and/orcutting tissue to achieve any combination of diagnostic or therapeuticeffects, various examples of which will be described below in greaterdetail.

As noted above, generator (14) is a single output generator that candeliver power through a single port to provide both RF and ultrasonicenergy such that these signals can be delivered separately orsimultaneously to end effector (20) for cutting and/or sealing tissue.Such a single output port generator (14) has a single output transformerwith multiple taps to provide power, either for RF or for ultrasonicenergy, to end effector (20) depending on the particular treatment beingperformed on the tissue. For example, generator (14) may deliver energywith higher voltage and lower current to drive ultrasonic transducer(24), with lower voltage and higher current as required to drive RFelectrodes (30) for sealing tissue, or with a coagulation waveform forspot coagulation using either monopolar or bipolar electrosurgicalelectrodes. The output waveform from generator (14) can be steered,switched, or filtered to provide the desired frequency to end effector(20) of surgical instrument (12).

II. Blade Temperature Control

While ultrasonic blade (28) of FIG. 1 generally begins at an initial,room temperature upon an initial application of ultrasonic energy totissue, the temperature tends to increase with each successive use,particularly when successive uses are over a relatively short time.Increasing temperatures of ultrasonic blade (28) tend to affect sealingand transection of the tissue in generally any method of operatingsurgical system (10), such as those described herein, particularly withrespect to ultrasonic energy. More particularly, relatively highertemperatures tend to increase the likelihood of inadvertentlytransecting the tissue while sealing or even transecting the tissue tooquickly prior to sealing and may not be accounted for in operation.While such effects may be trivial in some tissue treatments, adjustmentsto one or more electrical parameters of ultrasonic energy as describedbelow are configured to limit the temperature of ultrasonic blade (28)for providing greater consistency in successive applications ofultrasonic energy to tissue. Such temperature limits to ultrasonic blade(28) are also configured to preserve the useful life of the clamp pad ofclamp arm (26), which may be damaged by relatively high temperatures.

In the present example, FIG. 3 illustrates a method (1110) of, to atleast some extent, controlling a temperature of ultrasonic blade (28) ofsurgical system (10) of FIG. 1 in use by monitoring changing ultrasonicfrequencies due to temperature fluctuations to limit the temperature toan upper temperature limit. The clinician initially activates ultrasonicenergy and RF energy in a step (1112) at an initial time, T₀, andapplies the energy to tissue as described herein. Simultaneously,controller (46) interrogates ultrasonic blade (28) with a measurement ofa first ultrasonic frequency at the initial time, T₀, and stores thefirst ultrasonic frequency measurement in a step (1114). After the firstultrasonic frequency measurement in step (1114), controller (46) againinterrogates ultrasonic blade (28) with another measurement of a secondultrasonic frequency at a following time, T₁, and stores the secondultrasonic frequency measurement in a step (1116). Each of the first andsecond ultrasonic frequencies is accessed and applied to a calculationof a frequency parameter change from the first ultrasonic frequency tothe second ultrasonic frequency in a step (1118). In one example, thefrequency parameter change may be calculated based on a baselinefrequency measured and stored in the EEPROM during production.

Controller (46) compares the calculated frequency parameter change toprior data of ultrasonic frequencies and correlates the calculatedfrequency parameter change from step (1118) to a current bladetemperature in a step (1120). Based on the current blade temperature,controller (46) adjusts at least one electrical power parameter of anoutput of the ultrasonic energy in response to reaching a predeterminedfrequency parameter change threshold in a step (1122) and thereby limitcurrent temperature of ultrasonic blade (28) in a step (1124). In oneexample, RF and ultrasonic energies continued to be applied in view ofthe adjusted electrical parameters until the tissue is sealed in a step(1126), while inhibiting transection of the tissue and/or reducingdamage to clamp arm (26). In another example, the output of ultrasonicenergy is terminated while RF energy continues to be applied in view ofthe adjusted electrical parameters until the tissue is sealed. Once thetissue is sealed, RF and ultrasonic energies are terminated. While theabove description of method (1110) includes measurement and adjustmentsrelated to ultrasonic energy, it will be appreciated that suchmeasurements and adjustments are not intended to be unnecessarilylimited to only ultrasonic energy.

FIG. 4 illustrates a more particular version (1210) of the method (1110)(see FIG. 3) discussed above with one example of ultrasonic frequencymeasurements represented by reference numeral (1211) in FIG. 5. Version(1210) of the present example begins with activation of ultrasonic andRF energies to initiate sealing in step (1112) while simultaneouslymeasuring initial ultrasonic frequency in step (1114). Controller (46)then measures a first interrogation ultrasonic frequency of ultrasonicblade (28) in a step (1212) followed by a calculation of a frequencyparameter change based on the initial ultrasonic frequency of step(1114) and the first interrogation ultrasonic frequency of step (1212)in a step (1214). Stored predetermined data correlations (1216) of bladetemperature to frequency parameter change that are configured to inhibittissue transection are accessed by controller (46) in a step (1218).Step (1218) thereby correlates the frequency parameter change of step(1214) based on the predetermined data correlations (1216) to a currentblade temperature in real-time.

A step (1220) compares the current blade temperature from step (1218) toa predetermined temperature limit for ultrasonic blade (28) to determinewhether the current blade temperature has increased to at least thepredetermined temperature. In the event that the current bladetemperature has not increased to the predetermined blade temperaturelimit, step (1212) through step (1220) repeatedly loop until the currentblade temperature is at least the predetermined temperature. Once thecurrent blade temperature is at least the predetermined bladetemperature in step (1220), controller (46) sets a predeterminedfrequency parameter change threshold on the ultrasonic energy in a step(1222). In the present example, ultrasonic frequencies (1211) tend todecrease with increasing temperature as illustrated in FIG. 5, whichidentifies an exemplary predetermined frequency parameter changethreshold (1223), and may be monitored by a difference between at leasttwo ultrasonic frequency measurements (1211) over time or a slope ofultrasonic frequency. In response to this setting, a step (1224) adjustsat least one power parameter of the ultrasonic energy to limitultrasonic energy to the predetermined frequency parameter changethreshold (1223) and, in turn, limits the current blade temperature toinhibit transection of the tissue in a step (1226).

Controller (46) then measures a second interrogation ultrasonicfrequency in a step (1228) followed by a determination of whether thetissue is sealed in a step (1230). In the event that the tissue issealed, controller (46) terminates ultrasonic and RF energies in step(1128) as discussed above. However, in the event that the tissue is notyet sealed, controller (46) determines if the second interrogationultrasonic frequency is limited to the predetermined frequency parameterchange threshold (1223) in a step (1232). If the second interrogationultrasonic frequency is limited to the predetermined frequency parameterchange threshold (1223), then step (1228) and step (1230) repeat. If thesecond interrogation ultrasonic frequency exceeds the predeterminedfrequency parameter change threshold (1223), then further adjustment andlimiting per step (1224) and step (1226) followed by step (1228) andstep (1230) repeat. These repetition loops based on step (1232) continueuntil the tissue is sealed in step (1230) followed by RF and ultrasonicenergy termination in step (1128).

Furthermore, in one or more examples, transfer functions based onfrequency measurements (1211) and/or frequency slope may also beconfigured to control the output of the ultrasonic energy in order tocontrol blade temperature. In any case, blade temperature control mayalso be configured to reduce and/or minimize temperature differentialbetween ultrasonic blade (28) and clamp arm (26) by further controllingRF energy applied to the tissue via RF electrodes (30) for relativelyeven temperature changes across tissue from ultrasonic blade (28) toclamp arm (26).

III. Exemplary Combinations

The following examples relate to various non-exhaustive ways in whichthe teachings herein may be combined or applied. It should be understoodthat the following examples are not intended to restrict the coverage ofany claims that may be presented at any time in this application or insubsequent filings of this application. No disclaimer is intended. Thefollowing examples are being provided for nothing more than merelyillustrative purposes. It is contemplated that the various teachingsherein may be arranged and applied in numerous other ways. It is alsocontemplated that some variations may omit certain features referred toin the below examples. Therefore, none of the aspects or featuresreferred to below should be deemed critical unless otherwise explicitlyindicated as such at a later date by the inventors or by a successor ininterest to the inventors. If any claims are presented in thisapplication or in subsequent filings related to this application thatinclude additional features beyond those referred to below, thoseadditional features shall not be presumed to have been added for anyreason relating to patentability.

Example 1

A method of limiting an ultrasonic blade temperature of a surgicalinstrument with an ultrasonic blade configured to apply ultrasonicenergy to tissue, the method comprising: (a) increasing the temperatureof the ultrasonic blade toward an upper temperature limit; (b) adjustingat least one power parameter of the ultrasonic energy in response toreaching a predetermined frequency parameter change threshold in theultrasonic blade; and (c) limiting the temperature of the ultrasonicblade to the upper temperature limit.

Example 2

The method of Example 1, further comprising: (a) measuring a firstultrasonic frequency of the ultrasonic blade; (b) measuring a secondultrasonic frequency of the ultrasonic blade after measuring the firstultrasonic frequency; and (c) calculating a frequency parameter changebetween the measured first and second ultrasonic frequencies of theultrasonic blade.

Example 3

The method of Example 2, wherein the first ultrasonic frequency of theultrasonic blade is an initial ultrasonic frequency of the ultrasonicblade.

Example 4

The method of any one or more of Examples 1 through 3, furthercomprising correlating the frequency parameter change of the ultrasonicblade to the temperature of the ultrasonic blade.

Example5

The method of Example 4, wherein correlating the frequency parameterchange further includes correlating the frequency parameter change ofthe ultrasonic blade to the temperature of the ultrasonic blade based ona plurality of predetermined data correlations of blade temperature tofrequency parameter stored on a controller of the surgical instrument.

Example 6

The method of any one or more of Examples 1 through 5, furthercomprising determining that the temperature of the ultrasonic blade hasincreased to the upper temperature limit.

Example 7

The method of any one or more of Examples 1 through 6, wherein limitingthe temperature of the ultrasonic blade further includes limiting thetemperature of the ultrasonic blade to thereby inhibit transection of atissue.

Example 8

The method of any one or more of Examples 1 through 7, furthercomprising measuring a third ultrasonic frequency of the ultrasonicblade.

Example 9

The method of Example 8, further comprising determining that a tissueengaged with the ultrasonic blade is not sealed.

Example 10

The method of Example 9, further comprising: (a) determining that thethird ultrasonic frequency of the ultrasonic blade reached thepredetermined frequency parameter change threshold; and (b) furtheradjusting the at least one power parameter of the ultrasonic energy inresponse to reaching the predetermined frequency parameter changethreshold in the ultrasonic blade.

Example 11

The method of Example 9, further comprising: (a) determining that thethird ultrasonic frequency of the ultrasonic blade is less than thepredetermined frequency parameter change threshold; and (b) remeasuringthe third ultrasonic frequency of the ultrasonic blade.

Example 12

The method of any of Example 8, further comprising determining that atissue engaged with the ultrasonic blade is sealed.

Example 13

The method of Example 12, further comprising terminating the ultrasonicenergy based on the determination that the tissue engaged with theultrasonic blade is sealed.

Example 14

The method of any one or more of Examples 1 through 13, wherein limitingthe temperature of the ultrasonic blade further includes inhibitingdamage to a clamp arm configured to compress a tissue against theultrasonic blade.

Example 15

The method of any one or more of Examples 1 through 14, furthercomprising setting the predetermined frequency parameter changethreshold.

Example 16

A method of determining an ultrasonic blade temperature of a surgicalinstrument having an ultrasonic blade configured to be driven by anultrasonic energy, the method comprising: (a) measuring a firstultrasonic frequency of the ultrasonic blade; (b) measuring a secondultrasonic frequency of the ultrasonic blade after measuring the firstultrasonic frequency; (c) calculating a frequency parameter changebetween the measured first and second ultrasonic frequencies of theultrasonic blade; and (d) correlating the frequency parameter change ofthe ultrasonic blade to the temperature of the ultrasonic blade tothereby determine the temperature of the ultrasonic blade.

Example 17

The method of Example 16, wherein correlating the frequency parameterchange further includes correlating the frequency parameter change ofthe ultrasonic blade to the temperature of the ultrasonic blade based ona plurality of predetermined data correlations of blade temperature tofrequency parameter stored on a controller of the surgical instrument.

Example 18

An ultrasonic surgical instrument, comprising: (a) an end effectorconfigured to actuate from a first configuration to a secondconfiguration, including: (i) an ultrasonic blade configured toselectively apply ultrasonic energy to tissue, and (ii) a jaw movablypositioned relative to the ultrasonic blade and configured to movebetween an open position and a closed position, wherein the jaw andultrasonic blade in the open position are configured to receive tissue,and wherein the jaw and ultrasonic blade in the closed position areconfigured to clamp the tissue; (b) a shaft assembly projectingproximally from the end effector; (c) a body projecting proximally fromthe shaft assembly, wherein the body includes an energy inputoperatively connected to the ultrasonic blade; and (d) a controlleroperatively connected to the ultrasonic blade and configured to measurean ultrasonic frequency of the ultrasonic blade, wherein the controllerhas a memory including a plurality of predetermined data correlationsthat correlate changes in measured ultrasonic frequency of theultrasonic blade to a blade temperature of the ultrasonic blade, whereinthe controller is configured to correlate the predetermined datacorrelations to the blade temperature of the ultrasonic blade.

Example 19

The ultrasonic surgical instrument of Example 18, wherein the controlleris further configured to limit the blade temperature to an uppertemperature limit.

Example 20

The ultrasonic surgical instrument of Example 18, wherein the memoryfurther includes a predetermined frequency parameter threshold, andwherein the controller is configured to adjust at least one powerparameter of the ultrasonic energy and limit the measured ultrasonicfrequency of the ultrasonic blade to the predetermined frequencyparameter threshold for limiting the temperature of the blade to anupper temperature limit.

IV. Miscellaneous

It should be understood that any one or more of the teachings,expressions, embodiments, examples, etc. described herein may becombined with any one or more of the other teachings, expressions,embodiments, examples, etc. that are described herein. Theabove-described teachings, expressions, embodiments, examples, etc.should therefore not be viewed in isolation relative to each other.Various suitable ways in which the teachings herein may be combined willbe readily apparent to those of ordinary skill in the art in view of theteachings herein. Such modifications and variations are intended to beincluded within the scope of any claims.

Any one or more of the teaching, expressions, embodiments, examples,etc. described herein may be combined with any one or more of theteachings, expressions, embodiments, examples, etc. described in U.S.patent application Ser. No. 15/967,758, entitled “Combination Ultrasonicand Electrosurgical Instrument with Clamp Arm Position Input and Methodfor Identifying Tissue State,” filed on May 1, 2018, publishes as U.S.Pub. No. 2018/0333182 on Nov. 22, 2018; U.S. patent application Ser. No.15/967,763, entitled “Combination Ultrasonic and ElectrosurgicalInstrument with Adjustable Energy Modalities and Method for SealingTissue and Inhibiting Tissue Resection,” filed on May 1, 2018, publishedas U.S. Pub. No. 2018/0333185 on Nov. 22, 2018; U.S. patent applicationSer. No. 15/967,770, entitled “Combination Ultrasonic andElectrosurgical Instrument with Adjustable Clamp Force and RelatedMethods,” filed on May 1, 2018, published as U.S. Pub. No. 2018/0333187on Nov. 22, 2018; U.S. patent application Ser. No. 15/967,777, entitled“Combination Ultrasonic and Electrosurgical Instrument and Method forSealing Tissue with Various Termination Parameters,” filed on May 1,2018, published as U.S. Pub. No. 2018/0333189 on Nov. 22, 2018; and/orU.S. patent application Ser. No. 15/967,784, entitled “CombinationUltrasonic and Electrosurgical Instrument and Method for Sealing Tissuein Successive Phases,” filed on May 1, 2018, published as U.S. Pub. No.2018/0333190 on Nov. 22, 2018. The disclosure of each of theseapplications is incorporated by reference herein.

Further, any one or more of the teachings, expressions, embodiments,examples, etc. described herein may be combined with any one or more ofthe teachings, expressions, embodiments, examples, etc. described inU.S. patent application Ser. No. 15/967,740, entitled “CombinationUltrasonic and Electrosurgical Instrument Having Electrical CircuitsWith Shared Return Path,” filed on May 1, 2018, published as U.S. Pub.No. 2018/0333177 on Nov. 22, 2018; U.S. patent application Ser. No.15/967,746, entitled “Combination Ultrasonic and ElectrosurgicalInstrument Having Slip Ring Electrical Contact Assembly,” filed on May1, 2018, issued as U.S. Pat. No. 10,945,778 on Mar. 16, 2021; U.S.patent application Ser. No. 15/967,747, entitled “Combination Ultrasonicand Electrosurgical Instrument Having Electrically Insulating Features,”filed on May 1, 2018, issued as U.S. Pat. No. 10,945,779 on Mar. 16,2021; U.S. patent application Ser. No. 15/967,751, entitled “CombinationUltrasonic and Electrosurgical Instrument Having Curved UltrasonicBlade,” filed on May 1, 2018, issued as U.S. Pat. No. 11,033,316 on Jun.15, 2021; U.S. patent application Ser. No. 15/967,753, entitled“Combination Ultrasonic and Electrosurgical Instrument Having Clamp ArmElectrode,” filed on May 1, 2018, issued as U.S. Pat. No. 11,058,472 onJul. 13, 2021; U.S. patent application Ser. No. 15/967,759, entitled“Combination Ultrasonic and Electrosurgical Instrument Having UltrasonicWaveguide With Distal Overmold Member,” filed on May 1, 2018, issued asU.S. Pat. No. 11,051,866 on Jul. 6, 2021; U.S. patent application Ser.No. 15/967,761, entitled “Combination Ultrasonic and ElectrosurgicalSystem Having Generator Filter Circuitry,” filed on May 1, 2018,published as U.S. Pub. No. 2018/0333184 on Nov. 22, 2018; and/or U.S.patent application Ser. No. 15/967,764, entitled “Combination Ultrasonicand Electrosurgical System Having EEPROM and ASIC Components,” filed onMay 1, 2018, published as U.S. Pat. No. 11,129,661 on Sep. 28, 2021. Thedisclosure of each of these applications is incorporated by referenceherein.

It should be appreciated that any patent, publication, or otherdisclosure material, in whole or in part, that is said to beincorporated by reference herein is incorporated herein only to theextent that the incorporated material does not conflict with existingdefinitions, statements, or other disclosure material set forth in thisdisclosure. As such, and to the extent necessary, the disclosure asexplicitly set forth herein supersedes any conflicting materialincorporated herein by reference. Any material, or portion thereof, thatis said to be incorporated by reference herein, but which conflicts withexisting definitions, statements, or other disclosure material set forthherein will only be incorporated to the extent that no conflict arisesbetween that incorporated material and the existing disclosure material.

Versions of the devices described above may have application inconventional medical treatments and procedures conducted by a medicalprofessional, as well as application in robotic-assisted medicaltreatments and procedures. By way of example only, various teachingsherein may be readily incorporated into a robotic surgical system suchas the DAVINCI™ system by Intuitive Surgical, Inc., of Sunnyvale, Calif.Similarly, those of ordinary skill in the art will recognize thatvarious teachings herein may be readily combined with various teachingsof any of the following: U.S. Pat. No. 5,792,135, entitled “ArticulatedSurgical Instrument For Performing Minimally Invasive Surgery WithEnhanced Dexterity and Sensitivity,” issued Aug. 11, 1998, thedisclosure of which is incorporated by reference herein; U.S. Pat. No.5,817,084, entitled “Remote Center Positioning Device with FlexibleDrive,” issued Oct. 6, 1998, the disclosure of which is incorporated byreference herein; U.S. Pat. No. 5,878,193, entitled “Automated EndoscopeSystem for Optimal Positioning,” issued Mar. 2, 1999, the disclosure ofwhich is incorporated by reference herein; U.S. Pat. No. 6,231,565,entitled “Robotic Arm DLUS for Performing Surgical Tasks,” issued May15, 2001, the disclosure of which is incorporated by reference herein;U.S. Pat. No. 6,783,524, entitled “Robotic Surgical Tool with UltrasoundCauterizing and Cutting Instrument,” issued Aug. 31, 2004, thedisclosure of which is incorporated by reference herein; U.S. Pat. No.6,364,888, entitled “Alignment of Master and Slave in a MinimallyInvasive Surgical Apparatus,” issued Apr. 2, 2002, the disclosure ofwhich is incorporated by reference herein; U.S. Pat. No. 7,524,320,entitled “Mechanical Actuator Interface System for Robotic SurgicalTools,” issued Apr. 28, 2009, the disclosure of which is incorporated byreference herein; U.S. Pat. No. 7,691,098, entitled “Platform Link WristMechanism,” issued Apr. 6, 2010, the disclosure of which is incorporatedby reference herein; U.S. Pat. No. 7,806,891, entitled “Repositioningand Reorientation of Master/Slave Relationship in Minimally InvasiveTelesurgery,” issued Oct. 5, 2010, the disclosure of which isincorporated by reference herein; U.S. Pat. No. 8,844,789, entitled“Automated End Effector Component Reloading System for Use with aRobotic System,” issued Sep. 30, 2014, the disclosure of which isincorporated by reference herein; U.S. Pat. No. 8,820,605, entitled“Robotically-Controlled Surgical Instruments,” issued Sep. 2, 2014, thedisclosure of which is incorporated by reference herein; U.S. Pat. No.8,616,431, entitled “Shiftable Drive Interface forRobotically-Controlled Surgical Tool,” issued Dec. 31, 2013, thedisclosure of which is incorporated by reference herein; U.S. Pat. No.8,573,461, entitled “Surgical Stapling Instruments with Cam-DrivenStaple Deployment Arrangements,” issued Nov. 5, 2013, the disclosure ofwhich is incorporated by reference herein; U.S. Pat. No. 8,602,288,entitled “Robotically-Controlled Motorized Surgical End Effector Systemwith Rotary Actuated Closure Systems Having Variable Actuation Speeds,”issued Dec. 10, 2013, the disclosure of which is incorporated byreference herein; U.S. Pat. No. 9,301,759, entitled“Robotically-Controlled Surgical Instrument with SelectivelyArticulatable End Effector,” issued Apr. 5, 2016, the disclosure ofwhich is incorporated by reference herein; U.S. Pat. No. 8,783,541,entitled “Robotically-Controlled Surgical End Effector System,” issuedJul. 22, 2014, the disclosure of which is incorporated by referenceherein; U.S. Pat. No. 8,479,969, entitled “Drive Interface for OperablyCoupling a Manipulatable Surgical Tool to a Robot,” issued Jul. 9, 2013;U.S. Pat. No. 8,800,838, entitled “Robotically-Controlled Cable-BasedSurgical End Effectors,” issued Aug. 12, 2014, the disclosure of whichis incorporated by reference herein; and/or U.S. Pat. No. 8,573,465,entitled “Robotically-Controlled Surgical End Effector System withRotary Actuated Closure Systems,” issued Nov. 5, 2013, the disclosure ofwhich is incorporated by reference herein.

Versions of the devices described above may be designed to be disposedof after a single use, or they can be designed to be used multipletimes. Versions may, in either or both cases, be reconditioned for reuseafter at least one use. Reconditioning may include any combination ofthe steps of disassembly of the device, followed by cleaning orreplacement of particular pieces, and subsequent reassembly. Inparticular, some versions of the device may be disassembled, and anynumber of the particular pieces or parts of the device may beselectively replaced or removed in any combination. Upon cleaning and/orreplacement of particular parts, some versions of the device may bereassembled for subsequent use either at a reconditioning facility, orby a clinician immediately prior to a procedure. Those skilled in theart will appreciate that reconditioning of a device may utilize avariety of techniques for disassembly, cleaning/replacement, andreassembly. Use of such techniques, and the resulting reconditioneddevice, are all within the scope of the present application.

By way of example only, versions described herein may be sterilizedbefore and/or after a procedure. In one sterilization technique, thedevice is placed in a closed and sealed container, such as a plastic orTYVEK bag. The container and device may then be placed in a field ofradiation that can penetrate the container, such as gamma radiation,x-rays, or high-energy electrons. The radiation may kill bacteria on thedevice and in the container. The sterilized device may then be stored inthe sterile container for later use. A device may also be sterilizedusing any other technique known in the art, including but not limited tobeta or gamma radiation, ethylene oxide, or steam.

Having shown and described various embodiments of the present invention,further adaptations of the methods and systems described herein may beaccomplished by appropriate modifications by one of ordinary skill inthe art without departing from the scope of the present invention.Several of such potential modifications have been mentioned, and otherswill be apparent to those skilled in the art. For instance, theexamples, embodiments, geometrics, materials, dimensions, ratios, steps,and the like discussed above are illustrative and are not required.Accordingly, the scope of the present invention is understood not to belimited to the details of structure and operation shown and described inthe specification and drawings.

We claim:
 1. A method of limiting an ultrasonic blade temperature of asurgical instrument with an ultrasonic blade configured to applyultrasonic energy to tissue, the method comprising: (a) increasing thetemperature of the ultrasonic blade toward an upper temperature limit;(b) in response to determining that the temperature of the ultrasonicblade has reached the upper temperature limit, setting a predeterminedfrequency parameter change threshold; (c) adjusting at least one powerparameter of the ultrasonic energy in response to reaching thepredetermined frequency parameter change threshold in the ultrasonicblade to limit the ultrasonic energy to the predetermined frequencyparameter change threshold; and (d) limiting the temperature of theultrasonic blade to the upper temperature limit.
 2. The method of claim1, further comprising: (a) measuring a first ultrasonic frequency of theultrasonic blade; (b) measuring a second ultrasonic frequency of theultrasonic blade after measuring the first ultrasonic frequency; and (c)calculating a frequency parameter change between the measured first andsecond ultrasonic frequencies of the ultrasonic blade.
 3. The method ofclaim 2, wherein the first ultrasonic frequency of the ultrasonic bladeis an initial ultrasonic frequency of the ultrasonic blade.
 4. Themethod of claim 2, further comprising correlating the frequencyparameter change of the ultrasonic blade to the temperature of theultrasonic blade.
 5. The method of claim 4, wherein correlating thefrequency parameter change further includes correlating the frequencyparameter change of the ultrasonic blade to the temperature of theultrasonic blade based on a plurality of predetermined data correlationsof blade temperature to frequency parameter stored on a controller ofthe surgical instrument.
 6. The method of claim 4, further comprisingdetermining that the temperature of the ultrasonic blade has increasedto the upper temperature limit.
 7. The method of claim 6, whereinlimiting the temperature of the ultrasonic blade further includeslimiting the temperature of the ultrasonic blade to thereby inhibittransection of a tissue.
 8. The method of claim 6, further comprisingmeasuring a third ultrasonic frequency of the ultrasonic blade.
 9. Themethod of claim 8, further comprising determining that a tissue engagedwith the ultrasonic blade is not sealed.
 10. The method of claim 9,further comprising: (a) determining that the third ultrasonic frequencyof the ultrasonic blade reached the predetermined frequency parameterchange threshold; and (b) further adjusting the at least one powerparameter of the ultrasonic energy in response to reaching thepredetermined frequency parameter change threshold in the ultrasonicblade.
 11. The method of claim 9, further comprising: (a) determiningthat the third ultrasonic frequency of the ultrasonic blade is less thanthe predetermined frequency parameter change threshold; and (b)remeasuring the third ultrasonic frequency of the ultrasonic blade. 12.The method of claim 8, further comprising determining that a tissueengaged with the ultrasonic blade is sealed.
 13. The method of claim 12,further comprising terminating the ultrasonic energy based on thedetermination that the tissue engaged with the ultrasonic blade issealed.
 14. The method of claim 1, wherein limiting the temperature ofthe ultrasonic blade further includes inhibiting damage to a clamp armconfigured to compress a tissue against the ultrasonic blade.
 15. Themethod of claim 1, further comprising setting the predeterminedfrequency parameter change threshold.
 16. A method of determining anultrasonic blade temperature of a surgical instrument having anultrasonic blade configured to be driven by an ultrasonic energy, themethod comprising: (a) measuring a first ultrasonic frequency of theultrasonic blade; (b) measuring a second ultrasonic frequency of theultrasonic blade after measuring the first ultrasonic frequency; (c)calculating a frequency parameter change between the measured first andsecond ultrasonic frequencies of the ultrasonic blade; (d) correlatingthe frequency parameter change of the ultrasonic blade to thetemperature of the ultrasonic blade to thereby determine the temperatureof the ultrasonic blade; (e) in response to determining that thetemperature of the ultrasonic blade has reached a predeterminedtemperature limit, setting a predetermined frequency parameter changethreshold; and (f) adjusting at least one power parameter of theultrasonic energy based on the determined temperature of the ultrasonicblade to limit the ultrasonic energy to the predetermined frequencyparameter change threshold.
 17. The method of claim 16, whereincorrelating the frequency parameter change further includes correlatingthe frequency parameter change of the ultrasonic blade to thetemperature of the ultrasonic blade based on a plurality ofpredetermined data correlations of blade temperature to frequencyparameter stored on a controller of the surgical instrument.
 18. Amethod of limiting an ultrasonic blade temperature of a surgicalinstrument with an ultrasonic blade configured to apply ultrasonicenergy to tissue, the method comprising: (a) activating the ultrasonicenergy to initiate sealing of the tissue; (b) measuring an initialultrasonic frequency of the ultrasonic blade; (c) measuring a firstinterrogation ultrasonic frequency of the ultrasonic blade; (d)calculating a frequency parameter change based on the measured initialultrasonic frequency and the measured first interrogation ultrasonicfrequency; (e) correlating the calculated frequency parameter change toa current temperature of the ultrasonic blade based on a plurality ofpredetermined data correlations of blade temperature to frequencyparameter change; (f) determining whether the current temperature of theultrasonic blade has reached a predetermined temperature limit; (g) inresponse to determining that the current temperature of the ultrasonicblade has reached the predetermined temperature limit, setting apredetermined frequency parameter change threshold; and (h) adjusting atleast one power parameter of the ultrasonic energy to limit theultrasonic energy to the predetermined frequency parameter changethreshold.
 19. The method of claim 18, further comprising: (a) measuringa second interrogation ultrasonic frequency of the ultrasonic blade; (b)determining whether the tissue is sealed; (c) in response to determiningthat the tissue is not sealed, determining whether the measured secondinterrogation ultrasonic frequency exceeds the predetermined frequencyparameter change threshold; and (d) in response to determining that themeasured second interrogation ultrasonic frequency exceeds thepredetermined frequency parameter change threshold, readjusting the atleast one power parameter of the ultrasonic energy to limit theultrasonic energy to the predetermined frequency parameter changethreshold.
 20. The method of claim 19, further comprising in response todetermining that the tissue is sealed, terminating the ultrasonicenergy.